Method of and apparatus for oxidation of bitumen



Sept- 29, 19-70 I o. bHERACC: 3,531,375

METHOD OF AND APPARATUS FOR OXIDATION OF BITUMEN Filed June 6, 1966 I i 2 Sh eets-Sheet 1 1 2o l6 l4 2| 4 4 ll IL;

' 2? 1 2| 2s A 3 3 I I l3 1 2s l INVENTOR.

OSCAR CHERACCI ATTORNEYS METHOD OF AND APPARATUS FOR OXIDATION OF BITUMEN I Filed June 6, 1966 O. CHERACCI Sept. 29, 1970 2 Sheets- Sheet B ATTORNEYS United States Patent Office Patented Sept. 29, 1970 US Cl. 196-123 2 Claims ABSTRACT OF THE DISCLOSURE Apparatus and method for oxidizing bitumen. The bitumen to be oxidized is partially charged into an upright cylindrical boiler, oxidizing air is introduced into the lower part of the charge at a multiplicity of circumferentially spaced, separate points in the charge; causing said air to withdraw bitumen from the lower portion of the charge at said spaced points to become intimately commingled with the drawn bitumen; simultaneously causing said mixture of commingled bitumen and air to be conveyed upwardly through the charge in a multiplicity of circumferentially spaced, separate confined streams independent of the remainder of the charge to a point spaced above the top of the charge, and thereafter discharging said bitumen by gravity back into the charge for recirculation.

This invention relates generally to a method of and apparatus for oxidizing bitumen.

A primary object of the invention is to provide a method and apparatus whereby bitumen may be quickly and easily oxidized to a product having desired physical properties.

Another object of the invention is to provide a method of oxidizing bitumen, wherein large quantities of air are brought into intimate contact with the bitumen, and the bitumen continuously recirculated with the air, so as to obtain a product of desired properties within a fraction of the time required in conventional oxidation methods.

Another object of the invention is to provide a method of oxidizing bitumen, wherein the principle of air-lift pumping is utilized to achieve a rapid and continuous circulation of the bitumen during oxidation.

A further object of the invention is to provide apparatus for use in the aforesaid process, which apparatus is of simple and inexpensive construction, and is characterized by the employment of conventional equipment and parts which are easily available, which can be quickly and easily assembled and disassembled, and which has virtually no mechanically-moving parts.

A still further object of the invention is to provide apparatus of the character described, in which the bitumen can be easily charged and discharged, and control of the operations. maintained throughout, with a minimum of labor or effort. 1

Other objects and advantages of my invention will be apparent during the course of the following description.

In the accompanying drawings forming a part of this specification, and in which like numerals are employed to designate like parts throughout the same,

FIG. 1 is a vertical cross-sectional view of apparatus used in effecting the oxidation of the bitumen;

FIG. 2 is a cross-sectional view, taken on the line 22 of FIG. 1;

FIG. 3 is a fragmentary cross-sectional view, taken on the line 33 of FIG. 1, and

FIG. 4 is a fragmentary cross-sectional view, taken on the line 44 of FIG. 3.

Referring more particularly to the drawings, the apparatus will be seen to comprise a boiler generally designated by reference numeral 1, which is walled-in by an oven 2, having a burner 3, the oven constituing means for heating the contents of the boiler 1.

The boiler consists of a vertical cylindrical wall 4, a concave bottom 5, and a convex dome or top 6. The dome or top 6 is provided with an inlet opening 7 for charging the boiler with bitumen, and the wall 4 is provided adjacent its lower end with an outlet 8 for discharging the oxidized bitumen after the oxidation is completed, it being understood that the outlet 8 is closed during the oxidizing operation.

The dome or top 6 is provided centrally thereof with an annular collar 9 from the upper end of which an annular flange 10 extends horizontally.

Secured to the flange 10 and extending vertically-downward through the top 6 and to points near the bottom 5, is a series of circumferentially-spaced conduits 11. The lower ends of these conduits extend into hollow elements 12, which may be referred to as air-lift pumps. Secured to the elements 12, in axial alignment with the conduits 12, but spaced therefrom, are short conduits 13, which extend to points adjacent the bottom 5.

The conduits 11 are provided with curved extensions 14, which extend into and support a tube 15, which is closed at its upper end, as by a closure 16. The tube 15 extends centrally through the collar 9 and to a level somewhat below the lower end of the collar 9. The tube 15 is also provided with an annular baflle plate 17.

The flange 10 also provides a support for a hood consisting of acylindrical portion 18, a cylindrical portion 19 of smaller diameter than the portion 18, and a conical portion 20, which interconnects the portions 18 and 19.

The apparatus further comprises a series of circumferentially spaced conduits 21, which extend through the top 6 and forwardly into the boiler 1, the lower ends of the conduits 21 being connected to and opening into the air-lift pumps 12.

The upper ends of the conduits 2 1 are connected to an annular manifold 22 disposed above the boiler 1, and which is provided with an air inlet 23. It may be noted, at this point, that the manifold 22 gradually decreases in vertical cross-sectional area, from a maximum adjacent the inlet 23 to a minimum at a point in the manifold which is diametrically opposite the inlet 23.

The apparatus further includes a conduit 24 which extends downwardly into the boiler 1 to a point adjacent the bottom 5 and is connected to an annular tube 25 having perforations therein, so that air or steam which is admitted into the conduit 24 may pass through the perforations in the tube 25 and into the boiler for the purpose of agitating the bitumen within the boiler.

A thermometer 26 is also provided for determining the temperature of the bitumen at all times.

A sampling tube 27 is also provided, which is open at its inner end 28, but is normally closed at its outer end 29. When the outer end 29 is opened, a sample of the bitumen may be obtained for the purpose of determining the composition and physical properties of the bitumen at any stage in the oxidizing process.

A sight tube 30 is also provided for the purpose of visually examining the contents of the boiler, primarily to determine the level of such contents.

The method or process of oxidizing the bitumen may now be described, with reference to the foregoing description of the apparatus or parts thereof.

The boiler is charged through the inlet opening 7, with the bitumen which is to be oxidized, the level of the bitumen being indicated at 31.

Air, furnished by a turbo-blower (not shown), is supplied at low pressure, i.e., 0.5-0.7 atmospheres, and in large quantities to the inlet 23, passing into the manifold 22, and thence into the conduits 21. The air is supplied at the normal temperature at which it is furnished by the turbo-blower, but this air may be heated, if desired, to facilitate the oxidation of the bitumen.

Due to the gradually diminishing cross-sectional area of the manifold 22, the volume of the air in all of the conduits 21 is maintained uniform, the variation in crosssectional area of the manifold compensating for differences in air pressure at different points in the manifold which would result if the manifold were of uniform crosssectional area throughout.

The air passes from the conduits 21 into the air-lift pumps 12 and mixes with the bitumen, forming a mixture in which, due to the great quantities of air which are supplied, the air is uniformly distributed, in the form of minute bubbles, thereby greatly reducing the density of the bitumen which passes upwardly through the conduits 11.

Due to the difference in density between the bitumen in the boiler and the aforesaid mixture of bitumen and air in the conduits 11, the bitumen in the boiler forces the aforesaid mixture upwardly and into the extensions 14 of the conduits 11, and thence into the tube 15.

The mixture which is discharged into the tube 15 falls by gravity into the boiler, but the air in the mixture becomes separated from the bitumen, collects in the space below the top 6 of the boiler, passing upwardly through the collar 9, around the baffle plate 17, into the hood 18-20-19, and thence into a cooling system and separators (not shown) wherein the particles of light oil which are entrained in or by the air, are gathered and separated from the air.

The bitumen in the boiler thus becomes quickly oxidized, as a result of the continuous or repeated circulation of the bitumen through the boiler, upwardly through the conduits 11, and again downwardly through the boiler.

This repeated circulation is a phenomenon similar to that obtained in the air-lift method of pumping water, wherein compressed air is supplied to the bottom of a water well and mixes with the water. By impregnating with air a column of water in a tube sunk into the water bed, the water is made lighter, so that the pressure of a column of air and Water in the bottom of the tube is less per square inch than that of the water outside in the well or in the rock, gravel, or sand strata, so that an upward flow is obtained.

After the oxidation of the bitumen has proceeded to the desired point, the operation is stopped, and the oxidized bitumen is discharged through the outlet *8.

An essential requisite for this method of oxidizing the bitumen is to provide an inflow into the boiler of great amounts of air finely distributed and mixed with the bitumen, so as to obtain rapid oxidation of the bitumen and the consequent rapid increase in the melting point of the bitumen.

The number of conduits and the respective diameters thereof may be varied in accordance with dimensions and volume of the boiler. The boiler may have a volume of 40 or more cubic meters, "but, in any event, the maximum number of conduits permitted by the size of the boiler, are installed.

The inflow of large quantities of air is necessary in order to obtain a good contact of oxygen-rich air with the bitumen to be oxidized. It would not be of any advantage to use up a great percentage of oxygen from the same air, as oxygen-impoverished air would slow down the process of oxidation. To obtain a rapid oxidation of the bitumen at a relatively low temperature and to avoid the decomposition of the bitumen to be oxidized, it is essential to have a great surface of contact between the bitumen and the air containing a normal amount of oxygen. Moreover, it is essential to have uniform oxidation, and this is obtained with a good and even circulation of the product in the boiler, that is, by having the contents of the boiler circulate 20 or more times per hour. This will avoid the result of having a mixture of over-oxidized or under-oxidized particles of bitumen, which would impair the characteristics or properties of the final product.

The apparatus and process which have been described are eminently staisfactory for providing the conditions required for quick oxidation, and assure precisely an intimate mixture of air with the bitumen, and a proper utilization of the air and bitumen. This condition of close contact exists throughout the process.

In this connection, it is to be noted that, in contrast to existing methods in which air and bitumen are mixed only to an extent permitted by the depth of the bitumen in a vessel, the air and bitumen, in the present process, are maintained in close contact with each other through a distance which is represented by the combined lengths of the conduits 11, 14 and 15. This increase in the length and time of contact has been found to be highly advantageous in accelerating the oxidation of the bitumen.

The conduits 24 and 25 may be used to admit air and steam simultaneously or alternately, thereby assuring circulation of the bitumen in the boiler during the warmingup period.

The thermometer 26 permits control of the temperature throughout the process of oxidation.

The apparatus and process enables a rapid increase in the melting point of the bitumen to be easily obtained, varying in accordance with the source of the raw material from which the bitumen was extracted. A melting point of 250 F. (Kramer-Sarnow) is easily reached with a timesaving of 5-6 times greater than that obtained with a conventional blowing system.

Other advantages include the simplicity of the installation, the low cost of the same, the absence of mechanically moving parts, and a minimum of maintenance.

It is to be understood that various changes may be made in the method and apparatus which has been described, without departing from the spirit of the invention or the scope of the appended claims.

Having thus described my invention, I claim:

1. Apparatus for oxidizing bitumen comprising an upright, generally cylindrical boiler for receiving a charge of bitumen to be oxidized, said charge occupying less than the total volume of the boiler, a multiplicity of circumferentially spaced conduits disposed within said boiler and extending from points adjacent the lower portion of the charge to points spaced above the charge for conducting a portion of the bitumen upwardly to points disposed above the charge; a multiplicity of circumferentially spaced second conduits extending from points at the lower end of the charge upwardly to points above the charge, means for introducing air in large quantities to the upper ends of said second-named conduits, said means comprising an annular manifold disposed above said boiler and communicating with said second-named conduits, and means placing the lower ends of one each of said first and said second-named conduits in communication in operative pairs, said last-named means including air lift pumps interconnecting said first and said second-named conduits and acting to 'withdraw bitumen from said charge and intermixing the withdra'wn bitumen with the air, said boiler being provided with a dome having a collar secured centrally therein, and a tube extending through said collar centrally thereof, and said first-named conduits being provided with extensions having discharge ends within said tube, said intermixed air and bitumen being conveyed upwardly through the first-mentioned conduits for discharge at said points disposed above the charge.

2. Apparatus, as defined in claim 1, wherein said collar is provided with a flange, and a hood is provided, which is mounted on said flange.

References Cited UNITED STATES PATENTS DANIEL E. WYMAN, Primary Examiner P. E. KONOPKA, Assistant Examiner US. Cl. X.R. 

